Why is it that when you convert from cmyk to rgb in ai, I get one set of rgb values. When I do the same in photoshop it gives me different values.
Colour all synced using ai 24.3 and ps 21.2.0.
Colour settings are Europe General Purpose 3 so always going from FOGRA39 to sRGB.
There is no such thing as an exact numerical color conversion from RGB to CMYK. It has even changed over the years also in Adobe products and even in PMS swatch books. The issue si much more complex than you are seeing as black point compensation and color profile affect the results you get.
The best is to write down your color conversions in a brand guide and use that, along with defined swatches in both RGB & CMYK color space. You also should make sure your program are synced using Adobe Bridge >> Edit >> Color Settings on a mac. The menu might be similar in windows.
Many thanks for your response. I am aware of colour sync and ensure that ai and ps are using the same. What is frustrating is that if you have colours synced, then I would expect both programs to convers colour consistently, if both using the same profiles. I consulted adobe who said ai and ps do convert colours differently. Just wanted to see if anyone else had experienced this.
How much different? Can you give examples?
So with the CMYK values of 100,0,0,0, in ai that converts to R 0, G 158, B, 226.
Doing the same process in photoshop gives R 0, G 159, B, 227.
There can be some rounding in the calculation of RGB values (going from 0-100% to 0-255), creating a small difference in value.
But your example, converting 100% Cyan results for me in both applications to R 0, G 159, B 227.
Color settings are the same as yours.
But my app versions are more recent: AI: 25.2.2 and Ps: 22.3.1.
The process I am doing in ai is File > Document Colour Mode > RGB, I get R 0, G 158, B, 226.
The process in PS I am doing is Image > Mode > RGB. R 0, G 159, B, 227.
So I am taking the rgb values after that conversion. I get R 0, G 159, B 227 in ai when in cmyk mode.
That is the result of rounding.